E205 🟡 Repair Required
Navien Error Code E205: Water Flow Sensor Failure
⚠️ Your Navien boiler has detected a water flow sensor failure, which could lead to system damage if not addressed.
How to Fix Navien Code E205
- Check if your boiler is making any unusual noises, which could indicate air in the system.
- Try bleeding the air from the system using the built-in air vent.
- If the issue persists, do not attempt to fix it yourself. Contact a professional HVAC technician.
What Does Navien Error Code E205 Mean?
The E205 error on your Navien boiler indicates a malfunction in the water flow sensor. This sensor is responsible for monitoring the water flow rate through your boiler. If it's not working correctly, your boiler may not heat water efficiently, leading to system issues. The most common causes for this error are a faulty sensor or air in the system.
Common Causes of Navien Code E205
- Faulty water flow sensor
- Air in the system
- Incorrect water flow rate
- Clogged or dirty sensor
Applicable Navien Models
Source Documentation
This error code is documented in 6 official Navien technical manuals.
NFB-H Installation & Operation ManualPage 116
ReasonHeating Supply Temp.Sensor
ActionCheck flow, thermistor connector.
Navien NCB-H Installation & Operation ManualPage 129
ReasonHeating Supply Temp.Sensor
ActionContact technical support at 1-800-519-8794.
Navien NFB-H Installation & Operation ManualPage 116
ReasonHeating Supply Temp.Sensor
ActionCheck flow, thermistor connector.
Navien NFC-H Installation & Operation ManualPage 127
ReasonAbnormal operation: heating supply thermistor
ActionAuto RESET
Navien NHB-H Installation & Operation ManualPage 119
ReasonHeating Supply Temp.Sensor
ActionCheck flow, thermistor connector.
Navien NPF Installation & Operation ManualPage 126
ReasonAbnormal supply water-temp sensor operation for lower limit
ActionThis error occurs when the water temperature for supply or return does not operate properly. ● Turn off the furnace, turn it on again and check if the furnace operates properly. ● If the furnace is continuously inoperable, contact Technical Support at 1-800-519-8794.
Need a Pro to Fix Navien Code E205?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Navien Tankless Water Heater Code E205
Water Flow Sensor OEM: 360-00010-00